EDISON -- A police officer today pleaded guilty in Superior Court in New Brunswick to lying to officers conducting an investigation of a township company.

Officer Adam Tietchen, 64, who has more than 29 years service with the department, pleaded guilty to a disorderly person's charged of obstruction of the administration of law, Middlesex County Prosecutor Bruce Kaplan said in joint statement Edison police Director Brian Collier and Edison Police Chief Thomas J. Bryan.

Under a plea agreement reached with Middlesex County Assistant Prosecutor Brian Gillet, Tietchen must resign from the police department, can never work in law enforcement, and will be sentenced to a probationary term of one year, according to the statement.

Tietchen has been suspended without pay since he was charged May 21, 2009.

According to Kaplan, Edison police were investigating the Birnwell Apparel company on Brunswick Avenue, where Tietchen had performed security work. Authorities today said the investigation of the company is on-going and declined to release any details.

On Feb. 3, police asked Tietchen if he knew an employee of the company, and Tietchen admitted knowing the man, but said he rarely spoke with him, Kaplan said.

However, investigators later determined Tietchen frequently talked with that employee, the prosecutor said.

Jim O'Neill, spokesman for the prosecutor office, said there was no allegation of Tietchen tipping off the employee about the investigation.

"Officer Tietchen not only betrayed the public trust, but he betrayed the dedicated men and women of the Edison Police Department. My administration has a zero tolerance policy concerning any type of police misconduct," Police Chief Bryan said.

Anyone with information on the on-going investigation of Birnwell Apparel is asked to call Lt. Greg Formica of the Edison Police Department at (732) 248-7424.

A message left with Steven Cahn, the Edison lawyer representing Tietchen was immediately returned.